The rules of boxing in the ring are generally governed The Marquess of Queensbury Rules. The Queensbury Rules (or Queensbury as they are generally known) is a set of generally accepted rules in the sport of boxing.
They were first published in London in 1867, and were named after John Douglas the 9th Marquess of Queensbury as he publicly endorsed the code. However, a little known fact is that they were actually written by a Welsh sportsman named John Graham Chambers.
Prior to the adoption of the Queensbury Rules, boxing was covered by the London Prize Ring Rules and many of the rules first laid down within these are still in effect today. So rules forbidding the use of head-butting, gouging, scratching, kicking, biting or hitting a man whilst he's down were first listed in the London Prize Ring Rules. However these rules were superseded by the Queensbury Rules.